Piano



C. F. STEIN April 3, 1934.

PIANO Filed May 25, 1932 2 Sheets-Sheet l April 3, 1934. c, F. STEIN 1,953,544

PIANO Filed May 25, 1932 2 Sheets-Sheet 2 Patented Apr. 3, 1934 UNITED STATES PATENT ICE 9 Claims.

My invention relates to pianos, and more particularly concerns the provision of means for improving the tonal characteristics of such instruments.

It is well known to those conversant with the principles of piano construction that the chief elements which combine in operation to produce piano tonal characteristics are the strings, the sounding-board, and the sounding-board-stringbridges, and that, While-other parts of the piano, such as the frame and the casing, may participate to a certain degree, their participation is necessarily subordinate to, and limited by, their more important functions generally indicated by their names. Modiiications and even radical changes in the construction and arrangement of these other parts of the piano have been proposed from time to time, and various attachments have been provided, but it appears that the effect, if not always the intention, was to increase the resonance of the instrument, as such, and to amplify or otherwise aiiect the tone initially produced through the co-operative and intimately related action of the three aforesaid chief elements. It is a signicant fact that, while such modifications, changes and attachments have been numerous and varied, and have extended over a great number of years, none of them have been generally adopted or accepted as Wholly satisfactory, presumably because the effects obtainable thereby could not be apportioned or distributed as desired to the different tones of the scale. On the other hand, the construction, relationship and co-operative action of the strings, the sounding-board, and the sounding board stringbridges remain today substantially the same as they have been since they were first developed. The present invention is directly concerned with improving the co-operative action of these three elements.

In the drawings, Figure l is a plan view, illustrating the general arrangement of such parts of a grand piano as are more directly associated with the present invention, and showing the structure embodying said invention in position with relation thereto;

Fig. 2 is a fragmentary transverse vertical sectional view, taken upon the line 2 -2 oi Fig. l, showing a portion of the sounding-board-bridge for the overstrung bass strings and a section of the corresponding portion of the structure embodying the present invention;

Fig. 3 is a fore-and-aft vertical sectional View, taken partly upon the line 3 3 of Fig. l, showing the arrangement of the parts near the treble (Cl. Sli-189) end of the scale, and, in addition, a diagrammatic outline of the piano key and hammer-action associated therewith;

Fig. 4 is a iragmentary vertical sectional view, taken upon the line 4 4 of Fig. 1; and

Fig. 5 is a detail vertical sectional view, showing a modified form or" construction.

it has been mentioned that modiiications and even radical changes in the structure of various parts of the piano have been devised, and various attachments have been provided, for increasing the resonance of the instrument and amplifying the tone thereof. Resonance chambers have been arranged in the structure of the casing, and between and even Within members of the frame, and have been constructed as separate units attached to these parts and, in some instances, attached to and bodily supported by the sounding-board. Experience has taught, however, that resonance chambers generally possess their own characteristic resonant frequencies or natural periods, and their employment usually results in greater ampliiication of the tones which correspond or are harmonic in frequency thereto, so that certain tones or zones of tones in the scale will be affected to a greater extent than others.

The present invention is embodied in resonance chambers or novel construction and arrangement, oi which the sounding-board and the soundingboard-string-bridges form essential parts, and which are so located, shaped and constructed as to be resonantly responsive to each and all oi the strings and therefore applied to all of the tones of the scale. The said location, shape and construction of the chambers are such that they may be designed for and embodied in the construction of any standard type of piano, without requiring any re-arrangement or special design of any other part or parts of such instruments.

Referring, now, to the drawings, it will be observed that l have illustrated my invention as embodied in a standard type ovelstrung grand piano, having the usual strings 1 and 2, soundingboard 3, and sounding-board-string-bridges 4 and 5. These parts are similarly arranged and cooperate in like manner in pianos of the upright type, and the construction embodying my invention may be equally well applied in the manner herein shown to such parts of such instruments, all of which is so evident that it has been considered unnecessary to illustrate such application. It is Well Known to those conversant with the art that what is technically termed the down-bearing ci the strings is transmitted to the soundingboard through the string-supporting soundingboard-string-bridges and, since the soundingboard is slightly crowned and its edge parts are firmly held from spreading, 'it follows that this down-bearing of the strings compresses the sounding-board until a balancing resistance is developed, under which conditions the soundingboard and the sounding-board-string-bridges are highly sensitive and responsive to vibrations of the strings. Since the present invention does not require or meditate any changes in the arrangement or relationship of these elements, it is deemed unnecessary to further describe the cooperative action thereof. It is important, however, to direct attention to t`.e fact that the structure which I shall next describe as embodying my invention is positioned between the strings and the sounding-board, is iirmly secured to the sounding-board and tc the sounding-boardstring-bridges to vibrate freely therewith, and is arranged for close co-operative association with the strings of the entire scale. The bass-stringbridge 5 may be offset or undercut (not shown) as is generally done in pianos of smaller size, or may be directly supported upon the sctmding-board, shown. Since the invention is shown applied in like manner to the strings l and 2 and to the main and bass string-bridges, 4 and 5, respectively, and to the corresponding portions of the sound'- ing-board 3, a descrip'tion of its application to the strings l, the main string-bridge 4, and the main portion of the sounding-board will suiiice.

Arranged throughout the length of the bridge 4 at the forward side thereof, that is, beneath the vibrating parts of the strings 1, I provide a resonance chamber t, having a top '7, ends 8 and 9, and side 10. The rearward edge-part of top l is let into and iirmly secured to the forward side of bridge 4, while the forward edge-part and the end-parts of top 7 are firmly secured to and upon side l0 and ends 8 and 9, respectively, the side 10 and ends 8 and 9 being, in turn, firmly secured to and upon sounding-board 3. Directly beneath the strings for each note of the scale, the top '7 is provided with separate openings l1, generally similar in width, but graduated in length, the shorter openings at the treble and the longer ones toward the bass. Such an arrangement of apertures may be employed throughout the entire scale, in which a single opening is positioned beneath the strings for each note, with the longer dimension of each opening lying parallel with the strings of its respective note, but a number of separate openings may be arranged in line in place of the longer single openings, if desired, as illustrated at lla in Figures l and Il. The distribution of the r ena.. lffects provided by chamber 6 for the di. crept tones of the scale is dependent upon various factors. The graduated width of the chamber determines, to a substantial degree, the resonance of the chamber itself as affecting the different parts of the scale, and it also determines the area of the sounding-board to which its resonant eiiects are applied, also in accordance with the different tones ci the scale. The height of the chamber is a factor which has to be considered in determining the aforesaid graduated width, and the height is, a considerable measure, dependent upon the distance between the strings and the sounding-board, since the top '7 with its openings 1i lla should be sufficiently close to the strings for the chamber 6 to receive and respond tc the vibratory action of a definite and selected portion of each string, and yet must not be so close as to be struck by the string during violent vibrations thereof. The tops 'l may be slanted slightly downward toward the front, as shown beneath string l in Figure 4;, to afford this clearance.

Comparative tests of instruments embodying my invention with other instruments not embodying it, but intended and believed to be similarly constructed in all other respects, disclose marked improvements in clearness and purity of tone, and a very noticeable and highly desirable quickening in the speaking of the fundamental tones of the dierent notes. I believe this to be due to the novel and highly important features of my invention which I have already mentioned, that is, the positioning of the structure embodying my invention between the strings and the sounding-board, its being iirmly secured to the sounding-board and to the sounding-boardstring-bridges tovibrate freely therewith, and its arrangement for close cil-operative association with the strings of the entire scale. With the openings 11 and 11a properly proportioned and correctly located beneath their respective strings l, and the correspondinOr portions of chamber 6 of the proper resonant frequency, it appears that the lower or simpler tone partials are selectively picked up by the chamber and transmitted thereby directly to a substantial area of the sounding-board.

The modicaticn illustrated in Figure 5 does not embody all of the features I have described, since the openings 1lb are not located so closely adjacent to the strings. In this modification, the chamber openings 1lb are arranged in the forward side 10 of the chamber and need not be so close together. They are near enough to the strings, however, to produce results to a certain extent similar to those I have described in connection with openings 11, and the action of the chamber 6 with respect to the soLuiding-board 3 and bridge 4 is the same. I therefore consider this modication to be within the scope of my invention.

I claim:

l. The combination, with the strings, sounding-board, and sounding-bcard-string-bridge of a piano, of a chamber arranged between said strings and said sounding-board outside of said sounding-board-string-bridge having a wall with openings therein positioned adjacent to said strings.

2. The combination, with the strings, sounding-board, and sounding-board-string-bridge of a piano, of a chamber arranged between said strings and said sounding-board outside of said sounding-board-string-bridge having a wall with openings therein presented to said strings.

3. The combination, with the strings, sounding-board, and sounding-board-string-bridge of a piano, of a chamber arranged upon said sounding-board outside of said sounding-board-stringbridge having a Wall with openings therein positioned adjacent to said strings.

4. The combination, with the strings, sounding-board, and sounding-board-string-bridge of a piano, of a chamber arranged upon said sounding-board and connected with said soundingboard-string-bridge, said chamber having a Wall with openings therein positioned adjacent to said strings.

5. The combination, with the strings and sounding-board of a piano, of a chamber arranged therebetween to extend transversely of said strings, said chamber being rectangular in cross-section and tapering in width toward the treble end of the instrument, said chamber being closed except for openings provided in one Wall thereof at intervals along its length, said openings being arranged in said wall each adjacent to the strings representing one note of the musical scale.

6. The combination, with the strings and sounding-board of a piano, of a chamber arranged therebetween to extend transversely of said strings, said chamber having one nat wall tapering in width and provided with a series of apertures, said strings and said wall being arranged spaced from each other to extend in approximately parallel and adjacent planes, and the apertures of said series being located in said Wall coincident with the spacing of the strings representing one note from those representing another note of the musical scale.

7. The combination, with the strings and sounding-board of a piano, of a chamber arranged therebetween to extend transversely of said strings, said chamber having one flat wall tapering in Width and provided with a series of elongated apertures, the length of said apertures being relatively graduated with the longer apertures located in the wider parts of said wall and the longer diameter of each said aperture extending lengthwise of the strings crossing said wall and representing one note of the musical scale.

8. The combination, with the strings and sounding-board of a piano, of a chamber arranged therebetween to extend transversely of said strings, said chamber having one Wall thereof formed by said sounding-board and having another wall occupying planes approximately parallel with and between the planes occupied by said strings and said sounding-board, the last said wall being tapered in width and provided with a series of apertures opening into said chamber, said apertures being located in said wall to provide separate chamber openings each adjacent to the strings representing a note of the musical scale.

9. The combination, with the strings, the sounding-board, and the sounding-board-stringbridge of a piano, of a chamber arranged upon said sounding-board to extend along said bridge adjacent to the vibratory end parts of said strings, the bottom and rearward walls of said chamber being formed by said sounding-board and said bridge, respectively, the forward wall of said chamber being formed by a strip secured to said sounding-board and extending tangentially to said bridge, and the top of said chamber being formed by a ilat wall firmly secured to said strip and said bridge and covering the space therebetween, the ends of the chamber thus dened being closed by end members secured to the two side and top and bottom members mentioned, and the top of said chamber having openings arranged therein each coincident with the strings crossing said chamber which represent a note of the musical scale.

CHARLES FREDERICK STEIN. 

